They are stored as strings if you run your
app with a not-PostgreSQL database.

Queuing system: Rails4 added the support for a queue to run background jobs. The queuing
API is very simple. The ActiveSupport::Queue class comes with a push method
that accepts any object, as long as that object defines a run method.

Example:

class TestJob

def run

puts "I am running!"

end

end

You can queue a job to print “I
am running!” in the background by pushing an instance of that class to
Rails.queue:

Rails.queue.push(TestJob.new)

=> "I am running!"

·

Strong Parameters: In Rails 4, a new pattern has been introduced
to secure your models from mass assignment. You can filter the parameters
passed to your model in the controller instead of ‘whitelisting’ the attributes
in your model using “attr_accessible”.

class PostController < ApplicationController

def create

@post = Post.create(params[:user])

...

end

end

You can protect against unexpected input
with declarations in the model using “attr_accessible”.